While the present invention may be applied in a variety of manners, it is foreseen that it is particularly well adapted for applications concerning vehicle refinishing. Portions adjacent to the area to be painted are generally masked to inhibit paint overspray from reaching and adhering to areas not intended to be painted.
One typical masking or protective procedure involves applying a paper mask or plastic mask over the area not to be painted. Such masks can be applied and secured by tape or similar means. They are generally stripped from the vehicle and discarded, after use. However, neither of these methods is fully acceptable at least because air currents can cause the paper or plastic to flutter and allow overspray to swirl behind the paper or plastic, or to tear and expose areas to the overspray.
Water-washable liquid masking compositions have been developed. Examples of such compositions are disclosed in U.S. Pat. Nos. 5,104,711; 5,028,350; 4,525,501; and 4,347,266. The system described in the '711 patent provides an example of such systems. According to the disclosure, the liquid masking composition comprises: solvent (typically water), a polyhydroxy liquid carrier (typically glycerol), which aids in dispersion of thickener and surfactant during formulation of the composition and which also operates as a plasticizer in the coating, a thickener or film former (typically xanthan gum), which provides desired rheological properties and which forms a film on the coated surface and surfactant. The composition is prepared by mixing together appropriate amounts of the various components. A portion of a vehicle to be masked is spray-coated (typically and preferably with an atomizing spray gun) with the liquid masking composition. As the masking solution spreads, it will form a continuous mask, i.e., film or coating. A portion of the vehicle (not coated with film) to be finished is then coated with automotive primer, paint, or enamel, with any overspray that occurs typically landing on the masking film. After painting is complete and the paint film is dry, the masking film is readily removed with a washing solution, typically water or soapy water.
The present invention concerns improvements to liquid masking solutions. The improvements concern means by which product performance is enhanced due to reduction in likelihood of damage to the vehicle paint coating from the masking solution or film. The term "paint coating" or variants thereof as used herein in this context is meant to refer to coatings comprising any of a variety of materials including for example, acrylic enamels, acrylic lacquers, polyurethanes, metal flake paints and other typical vehicle finishes.